Schedule tasks within scheduled interval of workpackage

[kostobog]

Requirements:

• Duration should be the average duration of the TC type
• Task scheduling should be scaled according to the WP plan (start and end time)
  1. reduce distances between task executions (start to start) (end to start)
  2. (optional) if scheduled tasks cannot fit in the WP schedule, scale task durations and reduce create distances. Scaling should be applied carefully. For example, prioritize scaling duration of tasks for which their work time is smaller than the schedule duration.

@blcham